The nature of science is a prevalent theme across United States national science education standards and frameworks as well as other documents that guide formal and informal science education reform. To support teachers in engaging their students in authentic scientific practices and reformed teaching strategies, research experiences for teachers offered in national laboratories, university research centers, and national field-sites promise opportunities to help teachers update their current understanding of STEM fields and experience firsthand how scientific research is conducted with the end goal of supporting more inquiry-based teaching approaches in their classrooms. This qualitative interpretive study used an adapted Views of Nature of Science and Views on Scientific Inquiry surveys and protocols to investigate changes in 43 practicing teachers' understandings about the nature of science and scientific inquiry as a result of participation in one of three summer science research programs. Each program provided participants with research experiences alongside professional researchers as well as activities intended to increase participants' abilities to provide inquiry-based science learning activities for their students. Data were collected using open-ended surveys pre-program, post-program and long-term follow-up surveys, semi-structured interviews, focus groups, along with researcher's observations and field-notes. Participation in these programs led to small, measurable enhancements in teachers' understandings of scientific inquiry and the nature of science. Teachers' prior experience with research was found to have the strongest relationship to their knowledge of the nature of science and scientific inquiry. The data in this study provides evidence that research experiences can provide valuable experiences to support teachers' improved knowledge of how science is conducted.